Subject: Re: [PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7 without CONFIG_XICS set

From: Michael Ellerman <[email-masked]>
Date: Tue, 17 Nov 2009 23:39:04 +1100

On Tue, 2009-11-17 at 12:07 +0000, Mel Gorman wrote:
> KConfig doesn't require CONFIG_XICS to be set with CONFIG_PSERIES but if
> it's not set, there are numerous small build errors. This is a small series
> of patches to allow CONFIG_XICS to be unset in the config.
> 
> XICS appears to be some sort of interrupt controller but I'm not sure how
> common it is on systems that require CONFIG_PSERIES. If CONFIG_PSERIES
> universally requires CONFIG_XICS, the better path might be to force it to
> be set.

It is indeed 'some sort of interrupt controller' :)

All the virtualised PSERIES systems have, or appear to have, a XICS. So
it's pretty common.

I think the only time you see an MPIC is on older machines, and even
then maybe only if you're running bare metal.

So it is pretty much required for a PSERIES kernel, but perhaps there
are cases where the BML guys want to be able to turn it off.

cheers